Vane pumps and methods of operating same

ABSTRACT

A vane pump ( 20 ) including: a housing ( 21 ), a first motor ( 23 ) arranged to rotate a shaft ( 22 ) mounted about the shaft axis, a rotor ( 24 ) mounted for rotation with the shaft, and a member ( 28 ) having a surface ( 29 ) and having a member axis. The member is movable relative to the shaft axis through a permissible range of motion which includes portions on either side of a null position. A vane ( 32 ) is movably mounted in each rotor slot, and has a distal end arranged to engage the member surface. The vanes define with the rotor and surface a plurality of chambers ( 33 A- 33 F). The individual volumes of the chambers vary as a function of the relative position between the rotor and surface. A second motor ( 31 ) is operatively arranged to selectively move the member relative to the shaft axis through the permissible range of motion. Movement of the member off-null in one direction along the range of motion will enable fluid flow in a first direction between the ports, while movement of the member off-null in the opposite direction along the range of motion will enable fluid flow in the opposite direction between the ports.

TECHNICAL FIELD

The present invention relates generally to vane pumps, and, more particularly, to improved stackable over-center vane pumps and methods of operating the same.

BACKGROUND ART

Vane pumps are, of course, known. These devices generally have a rotor mounted for rotation within a cavity in a body or member. A plurality of circumferentially-spaced slots extends radially into the rotor from its outer surface. A vane is slidably mounted in each slot, and has a distal end operatively arranged to engage a portion of the member wall defining the cavity. Often, the vanes are urged to move outwardly from the rotor by centrifugal force when the rotor rotates. These vanes define with the rotor and the member, a series of circumferentially-spaced chambers between a fluid inlet and a fluid outlet. The volumes of these chambers progressively increase or decrease, depending on the direction of rotation, as the rotor rotates within the member. These chambers carry fluid from the fluid inlet to the fluid outlet. Examples of such vane motors are representatively shown and described in U.S. Pat. No. 4,619,594, U.S. Pat. No. 5,037,283 and U.S. Pat. No. 6,763,797.

However, with such prior art vane pumps, it is normally necessary to reverse the direction of rotor rotation to change the direction of fluid flow through the pump.

Accordingly, it would be desirable to provide improved vane pumps that would allow the direction of fluid flow through the pumps to be reversed without having to change the direction of rotor rotation.

DISCLOSURE OF THE INVENTION

With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for purposes of illustration and not by way of limitation, the present invention broadly provides improved vane pumps.

In one form, the improved vane pump (20) includes: a housing (21); a shaft (22) having a shaft axis (y₁-y₁), the shaft being mounted on the housing for rotation about the shaft axis; a first motor (23) operatively arranged to selectively rotate the shaft; a rotor (24) mounted for rotation with the shaft, the rotor having a plurality of circumferentially-spaced slots (26); a member (28) having a surface (29) and having a member axis (y₂-y₂), the member being movable relative to the shaft axis through a permissible range of motion (30) which includes portions (“−1”, “+1”) on either side of a null position (“0”); wherein the member axis (y₂-y₂) is coincident with the shaft axis (y₁-y₁) when the member is in the null position; a vane (32) movably mounted in each rotor slot and having a distal end arranged to sealingly and wipingly engage the member surface; the vanes defining with the rotor and surface a plurality of chambers (33A-33F), the individual volumes of the chambers varying as a function of the relative position between the rotor and surface; the housing having two fluid passageways (34, 34) operatively arranged to communicate with two of the chambers as a function of the angular position of the rotor relative to the housing; a second motor (31) operatively arranged to selectively move the member relative to the shaft axis through the permissible range of motion; wherein movement of the member off-null in one direction along the range of motion will enable fluid flow in a first direction between the ports; and wherein movement of the member off null in the opposite direction along the range of motion will enable fluid flow in the opposite direction between the ports.

The improved pump may further include a boundary seal (54) separating a wet portion (55) of the second motor from a dry portion (56) of the second motor. The second motor may have one portion (58) arranged on one side of the seal, and may have another portion (59) arranged on the other side of the seal. The one portion may include a permanent magnet (58), and the other portion may include a coil (59).

The member may be mounted on the housing.

In one form, the member may be mounted on the housing by a flexure member (40).

The range of member motion may be arcuate, linear or rotational.

A resilient member (41) may be arranged to act between the housing and the member for urging the member to move toward the null position.

In another form, the improved vane pump (20) may include: a housing (21); a shaft (22) having a shaft axis (y₁-y₁), the shaft being mounted on the housing for rotation about the shaft axis; a first motor (23) mounted on the housing and operatively arranged to selectively rotate the shaft; a plurality of rotors (24 in FIG. 1; 51 in FIG. 5) mounted for rotation with the shaft at spaced locations therealong, each rotor having a plurality of circumferentially-spaced slots (26); a plurality of members (28), each member having a surface (57) and having a member axis (y₂-y₂), each member being associated with a respective one of the rotors and being movable relative to the shaft axis through a permissible range of motion (30 in FIG. 1) which includes portions on either side of a null position; wherein each member axis is coincident with the shaft axis when the associated member is in the null position; a vane (26) movably mounted in each rotor slot and having a distal end arranged to sealingly and wipingly engage the surface of the associated member; the vanes defining with the associated rotor and surface a plurality of chambers (33A-33F in FIG. 1; 62A-62F in FIG. 6), the individual volumes of the chambers varying as a function of the relative position between the associated rotor and surface; the housing having two fluid passageways (34, 34) operatively arranged to communicate with two of the chambers for each member as a function of the angular position of the rotor relative to the housing; a plurality of second motors (31) operatively arranged to selectively move the associated member relative to the shaft axis through its permissible range of motion; wherein movement of each member off null in one direction along the range of motion of such member will enable fluid flow in a first direction between the ports of such member; and wherein movement of each member off null in the opposite direction along the range of motion of such member will enable fluid flow in the opposite direction between the ports of such member.

The members may be stacked at axially-spaced locations along the shaft.

The fluid output of each member may be controllable independently.

The improved pump may further include a plurality of boundary seals (54). Each boundary seal may separate a wet portion (55) of an associated second motor from a dry portion (56) of such associated second motor. Each second motor may have one portion arranged on one side of the associated seal, and may have another portion arranged on the other side of such associated seal. The one portion may include a permanent magnet (58), and the other portion may include a coil (59).

Each member may be mounted on the housing by a flexure member (40).

The range of motion of each member may be arcuate, linear or rotational.

The pump may further include a resilient member (41) acting between the housing and each member for urging such member to move toward the null position.

In a third form, the improved vane pump (20) may include: a housing (21); a shaft (22) having a shaft axis (y₁-y₁), the shaft being mounted on the housing for rotation about the shaft axis; a first motor (23) operatively arranged to selectively rotate the shaft; a rotor mounted for rotation with the shaft, the rotor having a plurality of circumferentially-spaced slots (26); a member (28) having a surface (29) arranged to face the rotor and having a member axis (y₂-y₂), the member being movable relative to the shaft axis through a permissible range of motion (30) which includes portions (“−1”, “+1”) on either side of a null position (“0”); wherein the member axis is coincident with the shaft axis when the member is in the null position; a vane (30) movably mounted in each rotor slot and having a distal end arranged to engage the member surface; a second motor (31) operatively arranged to selectively move the member relative to the shaft axis through the permissible range of motion; the vanes defining with the rotor and surface a plurality of chambers (33A-33F), the individual volumes of the chambers varying as a function of the relative position between the rotor and surface; the housing having two fluid passageways (34, 34) operatively arranged to communicate with two of the chambers as a function of the angular position of the rotor relative to the housing; and wherein the direction of flow between the passageways is a function of the position of the member axis (y₂-y₂) relative to the shaft axis (y₁-y₁).

The direction of fluid flow between the passageways may be in one direction when the member has been moved off-null in one direction along the range of motion, and may be in the opposite direction when the member has been moved off-null in the opposite direction along the range of motion.

The pump may further include a boundary seal (54) separating a wet portion (55) of the second motor from a dry portion (56) of the second motor. The second motor may have one portion arranged on one side of the seal, and may have another portion arranged on the other side of the seal. The one portion may include a permanent magnet (58), and the other portion may include a coil (59).

In a fourth form, the improved vane pump (20 in FIG. 1; 50 in FIG. 5) may include: a shaft (22) having a shaft axis (y₁-y₁), the shaft being mounted for rotation about the shaft axis; a first motor (23) operatively arranged to selectively rotate the shaft about the shaft axis; a rotor (24) mounted for rotation with the shaft, the rotor having a plurality of circumferentially-spaced slots (26); a member (28) having a surface (29) and having a member axis (y₂-y₂), the member being movable relative to the shaft axis through a permissible range of motion (30) which includes portions (i.e., positions “−1” and “+1”, respectively) on either side of a null position (i.e., position “0”); wherein the member axis is coincident with the shaft axis when the member is in the null position; a vane (32) movably mounted in each rotor slot and having a distal end arranged to sealingly and wipingly engage the member surface; the vanes defining with the rotor and surface a plurality of chambers (33A-33F), the individual volumes of the chambers varying as a function of the relative position between the rotor and surface; a second motor operatively arranged to selectively move the member relative to the shaft axis through the permissible range of motion; and a boundary seal (54) separating a wet portion (55) of the second motor from a dry portion (56) of the second motor; and wherein the second motor has one portion (58) arranged on one side of the seal and has another portion (59) arranged on the other side of the seal.

The one portion may include a permanent magnet (58), and the other portion may include a coil (59).

Also provided is an improved method of operating a vane pump (20) that includes a housing (21), a rotor (24) having a rotor axis (y₁-y₁) and being rotatably mounted on the housing, the rotor having a plurality of circumferentially-spaced slots (26); a member (28) having a surface (29) arranged to face the rotor and having a member axis (y₂-y₂), the member being movable relative to the rotor axis through a permissible range of motion (30); wherein the member axis (y₂-y₂) is coincident with the rotor axis (y₁-y₁) when the member is in the null position; a vane (32) movably mounted in each rotor slot and having a distal end arranged to engage the member surface; the vanes defining with the rotor and surface a plurality of chambers (33A-33F), the individual volumes of the chambers varying as a function of the relative position between the rotor and surface; comprising the steps of: rotating the rotor in one angular direction about the rotor axis; selectively moving the member relative to the rotor; and varying the direction of fluid flow between the ports as by varying the position between the rotor and member axes.

The method may further include the step of varying the magnitude of the fluid flow between the ports by varying the position between the rotor and member axes.

The position between the rotor and member axes may be varied by moving the member relative to the rotor.

Accordingly, the general object of the invention is to provide an improved vane pump.

Another object is to provide an improved vane pump having a plurality of stackable pump elements.

Another object is to provide an improved vane pump having a plurality of stackable pump elements that may be controlled independently of one another.

Still another object is to provide an improved method of operating a vane pump.

These and other objects and advantages will become apparent from the foregoing and ongoing written specification, the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary schematic vertical sectional view of a first form of an improved vane pump.

FIG. 2 is fragmentary schematic horizontal sectional view thereof, taken generally on line 2-2 of FIG. 1.

FIG. 3 is a fragmentary schematic horizontal sectional view through a second form of the improved vane pump, this view showing the member as being movably mounted on the housing by means of a flexure member, this view showing the member as being in a rightwardly-displaced off-null position relative to the rotor.

FIG. 4 is a fragmentary schematic horizontal sectional view of another form of the improved vane pump, generally similar to FIG. 3, but shows the member as constrained for linear motion within bearings, and shows the member as being in a rightwardly-displaced off-null position.

FIG. 5 is a fragmentary schematic vertical sectional view showing a plurality of rotors and members being stacked at axially-spaced locations along the shaft.

FIG. 6 is a fragmentary schematic horizontal sectional view, taken generally on line 6-6 of FIG. 5, showing one rotor within its associated member.

FIG. 7 is a schematic view of a vane pump, generally similar to FIG. 4, showing the member as being in its null position relative to the rotor.

FIG. 8A is a view generally similar to FIG. 7, showing the member as having been moved rightwardly off-null and showing chamber 71A as having been filled with fluid from fluid port C₁.

FIG. 8B is a view similar to FIG. 8A, but shows the rotor as having been rotated in a clockwise direction through an arc of about 60° from the position shown in FIG. 8A.

FIG. 8C is a view similar to FIG. 8B, but shows the rotor as having been further rotated in a clockwise direction through an arc of about 60° from the position shown in FIG. 8B, and showing chamber 71A as being aligned with fluid port C₂.

FIG. 9A is a view generally similar to FIG. 7, showing the member as having been moved leftwardly off-null and showing chamber 71A as being aligned with fluid port C₂.

FIG. 9B is a view similar to FIG. 9A, but shows the rotor as having been rotated in a clockwise direction through an arc of about 60° from the position shown in FIG. 9A.

FIG. 9C is a view similar to FIG. 9B, but shows the rotor as having been further rotated in a clockwise direction through an arc of about 60° from the position shown in FIG. 9B, and showing chamber 71A as being aligned with fluid port C₁.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions or surfaces consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this invention. As used in the following description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.

Referring now to the drawings, the present invention broadly provides improved vane pumps, and improved methods of operating same.

In FIGS. 1 and 2, a first form of the improved vane pump is generally indicated at 20. This pump is shown as broadly as including an annular housing 21, a shaft 22 having a vertical shaft axis y₁-y₁, a first motor 23 mounted on the housing and operatively arranged to selectively rotate the shaft about axis and a rotor 24 mounted on the lower end of the shaft for rotation therewith.

The rotor is shown as being a vertically-elongated cylindrical member having an outwardly-facing vertical cylindrical surface 25 of radius R₁. A plurality of circumferentially-spaced radial slots, severally indicated at 26, extend into the rotor from surface 25. Motor 23 is arranged to rotate rotor 24 at the appropriate angular speed in either angular direction, as desired, relative to the housing. However, unlike prior art vane pumps, the direction and speed of rotor rotation does not have to be changed or modified to reverse the direction of fluid flow between fluid ports C₁, C₂, as discussed infra.

An annular member, generally indicated at 28, surrounds the rotor. This member has an inwardly-facing vertical cylindrical surface 29 generated about a member axis y₂-y₂. In FIG. 1, the member axis y₂-y₂ is shown as being coincident with the rotor axis y₁-y₁. Hence, in FIG. 2, these coincident axes are indicated at y₁/y₂-y₁/y₂. In this embodiment, the member is movable relative to the shaft axis through a horizontal permissible range of motion, which includes portions on either side of (i.e., to the left and right of) a null position. This range of motion is schematically indicated at 30 in FIGS. 1 and 2. The null position is indicated by the center reference “0”, and the portions to the left and right thereof are indicated by “−1” and “+1”, respectively. Thus, the permissible range of motion of the member relative to the stator is from “−1” to “+1”, and the null position “0” is centered therebetween. However, this need not invariably occur. The extreme limits of the range of motion, “−1” and “+1”, respectively, may be equally distant from null position “0”, or not. In FIGS. 1 and 2, the member is shown as being in its null position such that axes y₁-y₁ and y₂-y₂ are coincident. The member can be moved in a horizontal direction, either leftwardly or rightwardly from the position shown in FIG. 2, by a motor 31.

A vane 32 is shown as being movably mounted in each rotor slot and as having a distal end arranged to sealingly and wipingly engage the member surface 29. The vanes define with the rotor and the surface a plurality of circumferentially-spaced chambers. In the embodiment shown, there are six vanes that subdivide the space between the rotor and the member into six chambers, severally indicated at 33 and individually identified with the suffix A, B, C, D, E and F. These vanes may be spring-biased into engagement with surface 29, or they may be moved outwardly by centrifugal force when the rotor rotates and/or may be fluid-biased into engagement with surface 29.

In FIGS. 1 and 2, the housing is shown as having two passageways, severally indicated at 34, that communicate with an opposite two of the chambers as a function of the angular position of the rotor of the housing. However, in another embodiment the passageways could communicate elsewhere with the chambers. For example, the passageways might simply communicate with the end wall of the chambers. Other forms may have more than two passageways. In the schematic embodiment shown in FIGS. 1 and 2, movement of the member off-null in one direction, either leftwardly or rightwardly, along the horizontal range of motion will enable fluid flow in a first direction between the ports C₁, C₂ (e.g., from C₁ to C₂), while movement of the member off-null in the opposite direction along the range of motion will enable fluid flow in the opposite direction between these ports (e.g., from C₂ to C₁). Thus, the direction of fluid flow between ports C₁, C₂ may be reversed by selectively moving the member along the permissible range of motion, without affecting either the speed or direction of rotor rotation.

FIG. 3 is a schematic view of another form of the inventive vane pump, generally indicated at 35. This embodiment also has a specially-configured hollow housing, generally indicated at 36, with a member 38 therewithin surrounding a rotor 39, as previously described. Here again, the distal ends of vanes 32 sealingly and wipingly engage the inwardly-facing surface 29 of the member. In this embodiment, member 38 is supported on the housing by means of a flexure member, generally indicated at 40. The lower end of member 38 is supported by a spring-biased telescopic linkage or resilient member, generally indicated at 41. This linkage includes an upper portion 42 pivotally connected to member 38, and a lower portion 43 pivotally connected to the housing and telescopically received within the upper portion. A coil spring 44 acts between the two linkage portions, and continually urges the pivotal connection between the linkage and the member to move downwardly. This tends to remove all backlash from the linkage holding suspended member 38, and, further, continuously urges the off-null displaced member to move back toward a null position.

In this arrangement, a second motor 31 is shown as being operatively arranged to selectively move member 38 either leftwardly or rightwardly off null, as desired relative to the shaft axis through a horizontal permissible range of motion which includes portions on either side (i.e., to the left and right of) of a null position “0”. Unlike the first embodiment in which the member was mounted for pure linear motion relative to the housing, in the embodiment shown in FIG. 3, member 38 is mounted for arcuate swinging movement about some effective pivot point along flexure member 40. However, because the extent of movement of member 38 relative to the rotor is small in relation to the distance between the effective pivot on flexure member 40 and the member axis, the permissible range of motion is again schematically indicated by a horizontal line 30 in FIG. 3. The null position is indicated by the reference “0”, and the portions to the left and right thereof are indicated by “−1” and “+1”, respectively. Thus, the range of motion of the member relative to the stator is approximated by the distance between “−1” to “+1”, with the null position “0” is centered therebetween. The member can be moved by a motor 34 either leftwardly or rightwardly from the position shown. In FIG. 3, member 38 is shown as having been shifted rightwardly relative to the rotor from its null position (i.e., from null position “0” to rightwardly-shifted position “+1”). This off-null displacement of the member causes the volumes of the vane chambers to vary as the rotor rotates in one angular direction. This causes fluid to be directed from port C₁ to port C₂, or vice versa, depending on the direction of rotor rotation.

FIG. 4 is a schematic view of another form of the improved vane pump having a member 38 arranged to be moved relative to a rotor 39. However, in this arrangement, the member is not mounted for pivotal or swinging arcuate movement relative to the housing. Rather, the member is constrained for linear sliding motion, both leftwardly and rightwardly, along a horizontal permissible range of movement defined by bearings, severally indicated at 49. Thus, this arrangement is generally similar to the first embodiment insofar as movement of the member relative to the rotor is concerned.

FIG. 5 is a schematic view of another form of vane pump, generally indicated at 50. This embodiment is shown as having a plurality of rotors, severally indicated at 51, and members, severally indicated at 52, mounted at longitudinally-spaced locations along a vertically-disposed shaft 53. Thus, the various vane pumps are “stacked” at various locations along the shaft. The shaft is arranged to be rotated about shaft axis y₁-y₁ by a first motor (not shown), as previously described. However, in this arrangement the various members 52 are mounted on bearings 54 for rotation relative to a housing 55. The positions of the various vane members may be controlled by individual second motors 31, again as previously described. Each vane pump is arranged to produce its own individual fluidic output as a function of the position of the associated member relative to its associated rotor. The several vane pumps are operable independently of one another. They do share the fact that their respective rotors rotate about common shaft 53. However, the positions of the various members are controllable independently of one another so that each vane pump has its own independently-controllable fluidic output. However, unlike the previously-described forms, in this embodiment, each second motor (not shown) is operatively arranged to rotate its associate member relative to the shaft axis y₁-y₁ to vary the position of the member axis relative to the shaft axis. A thin integrally-formed web-like annular boundary seal 54 separates a wet portion 55 of the second motor from a dry portion 56 of second motor 31. The second motor has one portion 58 arranged on one side of the seal and has another portion 59 arranged on the other side of the seal. The one portion may include a permanent magnet 58, and the other portion may include a coil 59.

FIG. 6 is a schematic view of a rotor and member of one vane pump, taken generally on line 6-6 of FIG. 5. This view is generally similar to FIG. 2, but shows the member surface 29 as being non-concentrically arranged within the member outer surface 56. Surface 56 is of radius R₃, and is generated about member axis y₃-y₃. Hence, rotation of the member relative to the housing (shown in FIG. 5) about member outer surface axis y₃-y₃ will cause non-concentric rotation of the member inner surface 29 relative to the rotor. This relative rotation between the member and housing will vary the volumes of chambers 62A-62F to vary the magnitude and direction of flow through the valve.

FIG. 7 is a schematic view of a portion of one vane pump, generally indicated at 65, showing a member 66 as being in its null position relative to a rotor 68. Vane pump 65 is generally similar to the vane pump shown in FIG. 4. Here again, there are six vanes, severally indicated at 69, mounted in slots in the rotor. Each of these vanes has a distal end that sealingly and wipingly engages an inwardly-facing surface 70 on the member. In FIG. 7, the member axis y₂-y₂ is shown as being coincident with the rotor axis The member is shown as having two fluid connections that communicate with two different vane chambers. The first is labeled C₁ and the second is labeled C₂.

FIG. 8A-c are a series of views, generally similar to FIG. 7, but showing the member as having been moved off-null to the right. In FIG. 8A, fluid from port C₁ is shown as entering vane chamber 71A. In FIG. 8B, the rotor is shown as having rotated vane chamber 71A from a position that communicates with fluid inlet C₁ in a clockwise direction through an arc-distance of 60° to an intermediate position. In FIG. 8C, the rotor is shown as having been further rotated in a clockwise direction relative to the member by an additional arc-distance of 60° such that vane chamber 71A has been rotated to a position at which it communicates with fluid outlet C₂. In FIGS. 8A-8C, a volume of fluid is shown as entering vane chamber 71A and being progressively conveyed in a clockwise direction relative to the member. Ultimately, the fluid is discharged through outlet C₂.

FIGS. 9A-9C are a series of a view that depict the member as having been shifted leftwardly off-null from the position shown in FIG. 7. Here again, fluid entering vane chamber 71A communicating with fluid inlet C₂ is progressively conveyed as the rotor rotates in a clockwise direction within the member, and is ultimately discharged at fluid port C₁.

Therefore, the present invention broadly provides an improved vane pump that broadly includes a housing, a shaft, a first motor, a rotor mounted on the shaft for rotation therewith, and a member having a surface and a member axis. The member axis is defined as being that location on the member when the member is in a null position relative to the rotor. Vanes are mounted on the rotor, and have distal ends arranged to engage the member surface. These vanes define with the rotor and surface a plurality of fluid chambers, the individual volumes of which vary as a function of relative position between the rotor and the member surface. The housing also has two fluid passageways that are operatively arranged to communicate with two of the chambers as a function of the angular position of the rotor relative to the housing. A second motor is operatively arranged to selectively move the member relative to the shaft axis through a permissible range of motion. Movement of the member off-null in one direction along the range of motion will enable fluid flow in the first direction between the ports, and movement of the member off-null in the opposite direction along the range of motion will enable fluid flow in the opposite direction between the ports.

One unique feature of the invention is that the direction of fluid flow through the vane pump may be changed by simply moving the member relative to the rotor, but without changing the direction or speed of rotation of the rotor about the shaft axis. In other words, the direction of fluid flow through the vane pump may be changed without adversely affecting the inertia of the moving rotor.

The present invention contemplates that may changes and modifications may be made. The shape and configuration of the rotor may be readily changed or modified. In the embodiment shown, the rotor has six slots, each of which is provided with a vane. This subdivides the space between the rotor and the member into six vane chambers. However, the size, configuration and shape of the rotor, as well as the number of vane slots, may be changed. The vanes may be moveable outwardly by centrifugal force. Alternatively, they may be spring-biased, or may be pushed outwardly by means of a fluid pressure.

Similarly, the shape and configuration of the member may be changed. In the embodiment shown, the member is shown as having a cylindrical inwardly-facing surface against which the distal ends of the vanes act. However, the invention is not limited to a member having an inwardly-facing cylindrical surface. Indeed, the member surface might be cylindrical, or might have some other shape, as desired. The member may be movable along a linear path, an arcuate path, or a rotational path. The arrangement and shape of the member and housing ports may be readily changed or modified as desired.

Therefore, while several forms of the improved vane pumps have been shown and described, and several modifications thereof discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit of the invention, as defined and differentiated by the following claims. 

What is claimed is:
 1. A vane pump, comprising: a housing; a shaft having a shaft axis, said shaft being mounted on said housing for rotation about said shaft axis; a first motor operatively arranged to selectively rotate said shaft; a rotor mounted for rotation with said shaft, said rotor having a plurality of circumferentially-spaced slots; a member having a surface and having a member axis, said member being movable relative to said shaft axis through a permissible range of motion which includes portions on either side of a null position; wherein said member axis is coincident with said shaft axis when said member is in said null position; a vane movably mounted in each rotor slot and having a distal end arranged to engage said member surface; said vanes defining with said rotor and surface a plurality of chambers, the individual volumes of said chambers varying as a function of the relative position between said rotor and surface; said housing having two fluid passageways operatively arranged to communicate with two of said chambers as a function of the angular position of said rotor relative to said housing; a second motor operatively arranged to selectively move said member relative to said shaft axis through said permissible range of motion; wherein movement of said member off null in one direction along said range of motion will enable fluid flow in a first direction between said ports; and wherein movement of said member off null in the opposite direction along said range of motion will enable fluid flow in the opposite direction between said ports.
 2. A vane pump as set forth in claim 1 wherein said member has passageways that communicate with said housing passageways and that terminate in ports at said surface.
 3. A vane pump as set forth in claim 1, and further comprising: a boundary seal separating a wet portion of said second motor from a dry portion of said second motor; and wherein said second motor has one portion arranged on one side of said seal and has another portion arranged on the other side of said seal.
 4. A vane pump as set forth in claim 3 wherein said one portion includes a permanent magnet, and said other portion includes a coil.
 5. A vane pump as set forth in claim 1 wherein said member is mounted on said housing.
 6. A vane pump as set forth in claim 5 wherein said member is mounted on said housing by a flexure member.
 7. A vane pump as set forth in claim 6 wherein said range of motion is arcuate.
 8. A vane pump as set forth in claim 1 wherein said range of motion is linear.
 9. A vane pump as set forth in claim 1, and further comprising: a resilient member acting between said housing and said member for urging said member to move toward said null position.
 10. A vane pump, comprising: a housing; a shaft having a shaft axis, said shaft being mounted on said housing for rotation about said shaft axis; a first motor mounted on said housing and operatively arranged to selectively rotate said shaft; a plurality of rotors mounted for rotation with said shaft at spaced locations therealong, each rotor having a plurality of circumferentially-spaced slots; a plurality of members, each member having a surface and having a member axis, each member being associated with a respective one of said rotors and being movable relative to said shaft axis through a permissible range of motion which includes portions on either side of a null position; wherein each member axis is coincident with said shaft axis when the associated member is in said null position; a vane movably mounted in each rotor slot and having a distal end arranged to engage the surface of the associated member; said vanes defining with the associated rotor and surface a plurality of chambers, the individual volumes of said chambers varying as a function of the relative position between said associated rotor and surface; said housing having two fluid passageways operatively arranged to communicate with two of said chambers for each member as a function of the angular position of said rotor relative to said housing; a plurality of second motors operatively arranged to selectively move the associated member relative to said shaft axis through its permissible range of motion; wherein movement of each member off null in one direction along the range of motion of such member will enable fluid flow in a first direction between the ports of such member; and wherein movement of each member off null in the opposite direction along the range of motion of such member will enable fluid flow in the opposite direction between the ports of such member.
 11. A vane pump as set forth in claim 10 wherein said member has passageways that communicate with said housing passageways and that terminate in ports at said surface.
 12. A vane pump as set forth in claim 10 wherein said plurality of members are stackable at axially-spaced locations along said shaft.
 13. A vane pump as set forth in claim 10 wherein the fluid output of each member is controllable independently.
 14. A vane pump as set forth in claim 10, and further comprising: a plurality of boundary seals, each boundary seal separating a wet portion of an associated second motor from a dry portion of such associated second motor; and wherein each second motor has one portion arranged on one side of the associated seal and has another portion arranged on the other side of such associated seal.
 15. A vane pump as set forth in claim 14 wherein said one portion includes a permanent magnet, and said other portion includes a coil.
 16. A vane pump as set forth in claim 10 wherein each member is mounted on said housing by a flexure member.
 17. A vane pump as set forth in claim 10 wherein the range of motion of each member is arcuate.
 18. A vane pump as set forth in claim 10 wherein the range of motion of each member is linear.
 19. A vane pump as set forth in claim 10, and further comprising: a resilient member acting between said housing and each member for urging such member to move toward said null position.
 20. A vane pump, comprising: a housing; a shaft having a shaft axis, said shaft being mounted on said housing for rotation about said shaft axis; a first motor operatively arranged to selectively rotate said shaft; a rotor mounted for rotation with said shaft, said rotor having a plurality of circumferentially-spaced slots; a member having a surface and having a member axis, said member being movable relative to said shaft axis through a permissible range of motion which includes portions on either side of a null position; wherein said member axis is coincident with said shaft axis when said member is in said null position; a vane movably mounted in each rotor slot and having a distal end arranged to engage said member surface; a second motor operatively arranged to selectively move said member relative to said shaft axis through said permissible range of motion; said vanes defining with said rotor and surface a plurality of chambers, the individual volumes of said chambers varying as a function of the relative position between said rotor and surface; said housing having two fluid passageways operatively arranged to communicate with two of said chambers as a function of the angular position of said rotor relative to said housing; and wherein the direction of flow between said passageways is a function of the position of said member axis relative to said shaft axis.
 21. A vane pump as set forth in claim 20 wherein said member has passageways that communicate with said housing passageways and that terminate in ports at said surface.
 22. A vane pump as set forth in claim 20 wherein the direction of fluid flow between said passageways is in one direction when said member has been moved off null in one direction along said range of motion, and is in the opposite direction when said member has been moved off null in the opposite direction along said range of motion.
 23. A vane pump as set forth in claim 20, and further comprising: a boundary seal separating a wet portion of said second motor from a dry portion of said second motor; and wherein said second motor has one portion arranged on one side of said seal and has another portion arranged on the other side of said seal.
 24. A vane pump as set forth in claim 23 wherein said one portion includes a permanent magnet, and said other portion includes a coil.
 25. A vane pump, comprising: a shaft having a shaft axis, said shaft being mounted for rotation about said shaft axis; a first motor operatively arranged to selectively rotate said shaft about said shaft axis; a rotor mounted for rotation with said shaft, said rotor having a plurality of circumferentially-spaced slots; a member having a surface and having a member axis, said member being movable relative to said shaft axis through a permissible range of motion which includes portions on either side of a null position; wherein said member axis is coincident with said shaft axis when said member is in said null position; a vane movably mounted in each rotor slot and having a distal end arranged to engage said member surface; said vanes defining with said rotor and surface a plurality of chambers, the individual volumes of said chambers varying as a function of the relative position between said rotor and surface a second motor operatively arranged to selectively move said member relative to said shaft axis through said permissible range of motion; and a boundary seal separating a wet portion of said second motor from a dry portion of said second motor; and wherein said second motor has one portion arranged on one side of said seal and has another portion arranged on the other side of said seal.
 26. A vane pump as set forth in claim 20 wherein said member has passageways that communicate with said housing passageways and that terminate in ports at said surface.
 27. A vane pump as set forth in claim 25 wherein said one portion includes a permanent magnet, and said other portion includes a coil.
 28. The method of operating a vane pump that includes a housing, a rotor having a rotor axis and being rotatably mounted on said housing, said rotor having a plurality of circumferentially-spaced slots; a member having a surface and having a member axis, said member being movable relative to said rotor axis through a permissible range of motion; wherein said member axis is coincident with said shaft axis when said member is in said null position; a vane movably mounted in each rotor slot and having a distal end arranged to engage said member surface; said vanes defining with said rotor and surface a plurality of chambers, the individual volumes of said chambers varying as a function of the relative position between said rotor and surface; comprising the steps of: rotating said rotor in one angular direction about said rotor axis; selectively moving said member relative to said rotor; and varying the direction of fluid flow between said ports as by varying the position between said rotor and member axes.
 29. The method as set forth in claim 28, and further comprising the additional step of: varying the magnitude of the fluid flow between said ports by varying the position between said rotor and member axes.
 30. The method as set forth in claim 28 wherein the position between said rotor and member axes is varied by moving said member relative to said rotor. 